Low-pressure casting multi-sprue process and device for aluminum alloy wheel

ABSTRACT

The present application relates to a low-pressure casting multi-sprue process and device for an aluminum alloy wheel. A multi-sprue casting method is adopted, and a plurality of sprues are arranged at the end of the inner flange of a wheel, so that molten aluminum enters at the inner flange first, then enters from a center sprue after a mold cavity at the rim is full of the molten aluminum. The mold assembly is pressurized and cooled after the mold cavity is full of the molten aluminum. During cooling, starting from the outer flange of the wheel filled with the molten aluminum last, side mold ring water coolers are started.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No. 201810204230.8, filed on Mar. 13, 2018, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present application relates to a low-pressure casting multi-sprue process and device for an aluminum alloy wheel.

BACKGROUND ART

At present, the conventional low-pressure casting of aluminum alloy wheels mostly adopts a center bottom injection process. Molten aluminum enters a mold cavity through a center sprue, flows across the spokes of a wheel, and then turns to fill the rim vertically, until the filling is completed. In the process of crystallization and solidification, the rim is at a distal end far away from the center sprue and is solidified first. Therefore, it is necessary to preferentially feed the rim by the spokes to delay the crystallization and solidification time of the spokes, which affects the mechanical properties of the aluminum alloy wheel materials. Particularly, the elongation of the spokes is generally low, which directly affects the overall quality of the wheel.

SUMMARY OF THE INVENTION

The object of the present application is to overcome the defects of the prior art, improves the quality of an aluminum alloy wheel and provide a low-pressure casting process and device for an aluminum alloy wheel, which focus on improving the elongation of spokes of the wheel and improving the casting production efficiency at the same time.

The technical scheme adopted by the application is: a low-pressure casting multi-sprue process for an aluminum alloy wheel adopts a multi-sprue casting method, and a plurality of sprues are provided at the end of the inner flange of a wheel, so that molten aluminum enters at the inner flange first, and then enters from a center sprue after a mold cavity at the rim is full of the molten aluminum, and is pressurized and cooled after the mold cavity is full of the molten aluminum.

During cooling, starting from the outer flange of the wheel filled with the molten aluminum last, side mold ring water coolers are started, and the side mold water coolers are close to the thick portions of the junctions of the spokes of the outer flange and the rim. Top mold coolers are also ring water coolers, the top mold water coolers are located on a top mold above the spokes, and a center water cooler is adopted in the center of the top mold to cool the center sprue.

By controlling the cooling time and the flow rate, the molten aluminum in the mold cavity crystallizes in sequence with the cooling of a mold. The crystallization progresses from the outer flange to the rim and the spokes at the same time until the inner flange and the center of the wheel are finally solidified, completing the entire casting process.

In the low-pressure casting process, the front sides of the spokes and the outer flange of the wheel casting are upward, and the rim and the inner flange are at the lower part.

A plurality of sprues are provided under the inner flange, the sprues are circular, and the number of the sprues varies according to the size of the wheel and is at least 8.

The center sprue is arranged under the center of the wheel, and is circular.

The side mold ring water coolers and the top mold ring water coolers are 15-40 mm away from the surface of the casting, and the flow rate of the cooling water is 150-400 L/hr.

A low-pressure casting device for an aluminum alloy wheel comprises a mold cooling system and a pressure casting system. The low-pressure casting device applies a multi-sprue mold assembly. The multi-sprue mold assembly comprises a bottom mold, a top mold, side molds and an ejection mechanism. The ejection mechanism is provided on the top mold for de-molding the casting. The lower part of the mold assembly communicate with a sprue basin, and the sprue basin is fixedly mounted on a bedplate of the low-pressure casting main machine, a holding furnace is below the bedplate, and the holding furnace connects with the central inlet of the sprue basin through a riser tube.

The top mold and the side molds are connected with a hydraulic control system of the low-pressure casting main machine.

A plurality of sprues are provided at the junction of the sprue basin and the molds, a sprue bushing made of ceramic is arranged at each sprue, and the molten aluminum is finally crystallized and solidified at the sprue in the pressure feeding phase after filling of the molten aluminum.

Since a plurality of sprues are arranged below the inner flange of the wheel and a center sprue is arranged in the center of the wheel at the same time, the filling time of the molten aluminum is shortened by half and the filling production efficiency is improved; because the outer flange begins to solidify in the cooling process, and at the same time the rim and the spokes are solidified in sequence, so that the crystallization and solidification time of the casting at the rim and the spokes is greatly shortened, the internal compactness of the casting is improved, the mechanical properties of the materials are good, and particularly, the elongation of the spokes is greatly improved; at the same time, the entire casting device is simple; and a sprue basin is added on the basis of ordinary low-pressure center casting. The whole process is simple and easy to operate.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a casting schematic diagram of a low-pressure multi-sprue process according to the present application.

In figures: 1—sprue basin, 2—bottom mold, 3—side molds, 4—top mold, 5—center sprue spreader water cooler, 6,7—top mold ring water coolers, 8—casting ejection rod, 9,10—side mold ring water coolers, 11—sprue bushing, 12—bedplate of the low-pressure casting main machine, 13—riser tube, 14—holding furnace.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, a low-pressure casting multi-sprue process and device for an aluminum alloy wheel according to the present application comprise a mold cooling system and a pressure casting system. The low-pressure casting device applies a multi-sprue mold assembly. The multi-sprue mold assembly comprises a bottom mold 2, a top mold 4, side molds 3, and a casting ejection rod 8. The casting ejection rod is provided on the top mold 4. The multi-sprue mold assembly is placed on a sprue basin 1. The mold cavity connects with the sprue basin through a plurality of sprue bushing 11. The sprue basin is assembled on a bedplate of a low-pressure casting main machine 12, and the sprue basin connects with a holding furnace 14 through a riser tube 13. Under the pressure, the molten aluminum in the holding furnace 14 enters into the sprue basin through the riser tube 13, and then enters into the mold cavity through the sprue bushings.

The mold cooling system comprises side mold ring water coolers 9, 10, top mold ring water coolers 6, 7, and a center sprue spreader water cooler 5. The side mold ring water coolers are quickly started after the mold cavity is full of the molten aluminum, a casting begins to crystallize and solidify at the outer flange, and the top mold ring water coolers and the center sprue spreader water cooler are sequentially started until the casting is solidified in sequence.

The foregoing descriptions of specific exemplary embodiments of the present application have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. A low-pressure casting multi-sprue process for an aluminum alloy wheel, wherein that the casting process adopts a multi-sprue casting method, and a plurality of sprues are provided at the end of the inner flange of a wheel, so that molten aluminum enters at the inner flange first, and then enters from a center sprue after a mold cavity at the rim is full of the molten aluminum; during cooling, starting from the outer flange of the wheel filled with the molten aluminum last, side mold ring water coolers are started, and the side mold water coolers are close to the thick portions of the junctions of the spokes of the outer flange and the rim; top mold coolers are also ring water coolers, the top mold water coolers are located on a top mold above the spokes, and a center water cooler is adopted in the center of the top mold to cool the center sprue.
 2. The low-pressure casting multi-sprue process for an aluminum alloy wheel according to claim 1, wherein that in the low-pressure casting process, the front sides of the spokes and the outer flange of the wheel casting are upward, and the rim and the inner flange are at the lower part.
 3. The low-pressure casting multi-sprue process for an aluminum alloy wheel according to claim 1, wherein that a plurality of sprues are provided under the inner flange, the center sprue is arranged under the center of the wheel, and the plurality of sprues and the center sprues are also circular.
 4. The low-pressure casting multi-sprue process for an aluminum alloy wheel according to claim 1, wherein that side mold ring water coolers and the top mold ring water coolers are 15-40 mm away from the surface of the casting, the flow rate of cooling water is 150-400 L/hr, and the side mold ring water coolers need to be started immediately after the mold cavity is full of the molten aluminum. 